Cystic fibrosis is one of the most common genetic diseases, affecting about 70,000 people worldwide. Mutations in a single gene, CFTR, clog the lungs with thick mucus. Despite gruelling physiotherapy to clear it, lung function steadily gets worse, lowering life expectancy to around 40 years.

They ran a trial involving 116 people, 62 of whom inhaled at least 9 monthly doses of the therapy while the rest got saline solution. After 12 months, those who received the therapy had on average 3.7 per cent better lung function than those who did not, as judged by the volume of air people could force out of their lungs in 1 second (The Lancet Respiratory Medicine, doi.org/52b).

“Although we know that the therapy isn’t ready to prescribe, I am delighted with the result – it’s better than I expected,” says Deborah Gill at the University of Oxford. The treatment involved inhaling a few millilitres of nebulised liquid each time, she says. The team is now working to develop a harmless virus which they hope will deliver the therapy more effectively.

This article appeared in print under the headline “Breakthrough at long last for cystic fibrosis gene therapy”